[Cargo] error: error parsing override file

I just upgraded to rust 1.49, and ever since then in 1 particular project I get an error completely foreign to me:

$ cargo clean
error: error parsing override file

The same result for cargo build, cargo test etc.

As far as I know I have no explicit "override file" anywhere; I certainly didn't author any.
Can anyone tell me what's going wrong here?

This error means that you have a file named rust-toolchain in the current directory or one of its ancestors, and the file is not in the expected format (a single line with the name of a rustup toolchain, or a TOML file with a specific layout).

It looks like older versions of rustup would ignore anything after the first line of rust-toolchain, but the latest version will throw an error if the file contains multiple lines but is not in TOML format.

1 Like

That explains it. The second line of the file was an old version of the contents:

# nightly-2018-05-13

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